A method for separating an integrated circuit using the conventional silicon wafer (hereinafter, IC chip) from a substrate has been proposed (Unexamined Patent Publication No. 2003-209073). The Unexamined Patent Publication No. 2003-209073 disclosed that a protective tape is adhered to a circuit surface of a semiconductor wafer, a dicing tape is adhered to a reverse surface, and the semiconductor wafer is diced with the protective tape to form a chip, then, a release tape is adhered to the diced protective tape, and then, the protective tape is heated to be deformed, lastly, the protective tape that is diced with the release tape is separated from the chip.
As a method for mounting an optical device chip on an electronic circuit board, a method for making a crystal growth of a buffer layer and an active layer over a semiconductor device, forming a plurality of optical devices, forming a separation groove by etching the active layer till the active layer reaches to the buffer layer, removing the semiconductor substrate by covering the surface of the active layer by the protective film, adhering the reverse side of the buffer layer to an extensible film with adhesive capable of being separated, breaking the buffer layer along with the separation groove, providing a space between adjacent devices by extending the extensible film, and fusion bonding and fixating a driver electrode of the optical device to the electronic circuit board by using the extensible film as a support jig (Unexamined Patent Publication No. 7-30209).